4AVD

C.lacteus nerve Hb in complex with CO

Summary for 4AVD

• Entry DOI: 10.2210/pdb4avd/pdb
• Related: 1KR7 1V07 2VYY 2VYZ 2XKG 2XKH 2XKI 4AVE
• Descriptor: NEURAL HEMOGLOBIN, PROTOPORPHYRIN IX CONTAINING FE, CARBON MONOXIDE, ... (7 entities in total)
• Functional Keywords: oxygen transport, nerve globin, heme reactivity, carbon monoxide, protein matrix tunnel
• Biological source: CEREBRATULUS LACTEUS (MILKY RIBBON-WORM)
• Total number of polymer chains: 1
• Total formula weight: 12534.71

Authors

Germani, F.,Pesce, A.,Venturini, A.,Moens, L.,Bolognesi, M.,Dewilde, S.,Nardini, M. (deposition date: 2012-05-25, release date: 2013-04-17, Last modification date: 2023-12-20)

Primary citation

Germani, F.,Pesce, A.,Venturini, A.,Moens, L.,Bolognesi, M.,Dewilde, S.,Nardini, M.
High Resolution Crystal Structures of the Cerebratulus Lacteus Mini-Hb in the Unligated and Carbomonoxy States.
Int.J.Mol.Sci., 13:8025-, 2012

PubMed Abstract: The nerve tissue mini-hemoglobin from Cerebratulus lacteus (CerHb) displays an essential globin fold hosting a protein matrix tunnel held to allow traffic of small ligands to and from the heme. CerHb heme pocket hosts the distal TyrB10/GlnE7 pair, normally linked to low rates of O(2) dissociation and ultra-high O(2) affinity. However, CerHb affinity for O(2) is similar to that of mammalian myoglobins, due to a dynamic equilibrium between high and low affinity states driven by the ability of ThrE11 to orient the TyrB10 OH group relative to the heme ligand. We present here the high resolution crystal structures of CerHb in the unligated and carbomonoxy states. Although CO binds to the heme with an orientation different from the O(2) ligand, the overall binding schemes for CO and O(2) are essentially the same, both ligands being stabilized through a network of hydrogen bonds based on TyrB10, GlnE7, and ThrE11. No dramatic protein structural changes are needed to support binding of the ligands, which can freely reach the heme distal site through the apolar tunnel. A lack of main conformational changes between the heme-unligated and -ligated states grants stability to the folded mini-Hb and is a prerequisite for fast ligand diffusion to/from the heme.

PubMed: 22942687
DOI: 10.3390/IJMS13078025

Experimental method

X-RAY DIFFRACTION (1.5 Å)